OBJECTIVE: To quantify resource utilization and costs incurred for patients who received transdermal fentanyl as their first long-acting analgesic for non-malignant pain, and to compare these with utilization and costs for similar patients dispensed other long-acting oral opioids. DESIGN: A retrospective matched cohort study using medical claims data from a large New England Insurer. PATIENTS: We identified 478 patients without cancer who received transdermal fentanyl during 1995-1998. We selected patients who had no previous long-acting opioid dispensings and were enrolled during the 180 days before and 30 days following the initial dispensing. We used propensity scores to identify a matched comparison group of 478 long-acting oral opioid users. RESULTS: Transdermal fentanyl and matched long-acting oral opioid users incurred identical median costs for outpatient medical services and prescriptions during 2 years of follow-up. A larger proportion of transdermal fentanyl patients were still taking their initial opioid analgesic at the end of the 2-year follow-up than were patients initially taking other long-acting opioids. Use of short-acting opioids tapered off more slowly among transdermal fentanyl patients than among long-acting opioid patients. In the first 6 months, the transdermal fentanyl patients had more hospital discharges than the long-acting oral opioid patients, but this difference appeared to reflect preexisting conditions. CONCLUSIONS: Users of fentanyl transdermal system and other long-acting opioids experienced essentially identical evolution of health services utilization and costs over a 2-year period. The choice of long-acting opioid analgesia does not appear to be a determinant of future medical costs.